The present invention is directed to a method and apparatus for treatment of the atmosphere, and more particularly, to a method for direct application of catalysts to a substrate and its use to treat atmospheric pollution and an apparatus to accomplish the same.
Controlling atmospheric pollution is a concern of increasing importance as the levels of various atmospheric pollutants continue to increase. One primary pollutant of concern is ozone. Various components in the atmosphere can lead to the production of ozone and these compounds include those produced by internal combustion engines. Volatile organic compounds and oxides of nitrogen released into the atmosphere are two primary precursors that lead to formation of ozone in the air via photocatalysis. Most pollution control measures are directed toward removing such ozone precursors at the emission sources.
Recently, a new technology has emerged for treatment of ozone at the ground level utilizing vehicle heat exchangers. Examples of this technology can be found in U.S. Pat. Nos. 6,214,303; 6,212,882; 6,200,542; and 6,190,627. These patents disclose methods for treating atmospheric pollutants by contacting the atmosphere with a catalytic composition on the surface of a substrate. The difficulty with this current technology is that getting the catalytically active compounds to adhere to the substrate requires the use of complicated binders, adhesive layers, and complex surface treatments. These procedures generally involve immersing the entire heat exchanger in a series of coating slurries to obtain a catalytically active surface. The equipment for carrying out these procedures is large and there is the additional difficulty of treating the residue. Finally, treatment of vehicle heat exchangers by these methods can tend to lead to a reduction in the heat exchange efficiency of the heat exchanger, which is undesirable.
It would be advantageous to provide a method for application of catalytically active substances to a substrate that is simple, can be incorporated easily into existing production facilities, is a one-step process, and that can be utilized to apply catalytically active substances to a variety of substrates in addition to heat exchangers.
In a first embodiment, the present invention is a method of forming a catalytically active surface on a substrate for treatment of atmospheric pollution comprising the steps of: providing a particle mixture comprising a catalytic metal; entraining the particle mixture into a flow of a gas, the gas at a temperature insufficient to cause thermal softening of the particle mixture; and directing the particle mixture entrained in the flow of gas through a supersonic nozzle placed opposite a substrate and accelerating the particle mixture to a velocity sufficient to result in adherence of the particle mixture onto the substrate, the adhered particle mixture forming a catalytically active surface capable of catalyzing the conversion of at least one of ozone, hydrocarbons, or carbon monoxide to oxygen, water and carbon dioxide, and carbon dioxide, respectively.
In a second embodiment, the present invention is a method of forming a catalytically active surface on a substrate for treatment of atmospheric pollution comprising the steps of: providing a particle mixture comprising a catalytic metal; entraining the particle mixture into a flow of a gas, the gas at a temperature insufficient to cause thermal softening of the particle mixture; and directing the particle mixture entrained in the flow of gas through a supersonic nozzle placed opposite a substrate comprising one of a radiator fin stock or a radiator core and accelerating the particle mixture to a velocity sufficient to result in adherence of the particle mixture onto the substrate, the adhered particle mixture forming a catalytically active surface metallically bonded to the substrate, the catalytically active surface being capable of catalyzing the conversion of at least one of ozone, hydrocarbons, or carbon monoxide to oxygen, water and carbon dioxide, and carbon dioxide, respectively.